1. Field of the Invention
The present invention relates to the formation of extruded products. More particularly, the present invention relates to processed food extrusion devices. The present invention is a single-head nozzle for shaped extrusions.
2. Description of the Prior Art
The mass production of formable products may be effected in a variety of ways including, but not limited to, by way of extrusion systems. An extruder is a device that forces mixed ductile or semi-soft solids through die openings of appropriate shape to produce continuous film, strips, tubing, or solid cylinders and polygons. The ductile or semi-soft solid is then subjected to further treatment, such as calendering, heating, etc., in order to finalize the shape and characteristics of the product created. Important aspects of the extrusion process necessary to ensure a product of acceptable characteristics include, but are not limited to: 1) the accuracy of the content of the mixture or formulation to be shaped or molded, 2) the viscosity of the formulation, 3) the rate of formulation flow through the extruder, and 4) the configuration of the nozzle, die, or head used to establish the preliminary shape of the extrudate prior to final processing.
Of particular interest in regard to the present invention is the configuration of the nozzle, die, or head used to establish the preliminary shape of the extrudate. The nozzle generally includes an inlet for receiving mixed material to be shaped. The nozzle also includes an opening with dimensions that fix the shape of the extrudate. For the most part, the inner dimensions of the nozzle are larger at the inlet than at the outlet. This arrangement is generally advantageous for the purpose of minimizing voids or air pockets in the extrudate. That is, the mixed material is compressed as it approaches the nozzle outlet, thereby forcing material into the voids or squeezing the voids to reduce their dimensions. It is to be noted that in most extrusion production processes, it is preferable to minimize voids in the extrudate.
Since void minimization is a goal in extrusion processes, the design of the nozzle outlet is critical, particularly as a function of the viscosity of the mixed material. For low-viscosity materials that set up almost immediately upon exiting the nozzle, the nozzle outlet configuration can be relatively complex. For more viscous materials, it is difficult to have a complex outlet configuration and still minimize voids. For that reason, among others, viscous mixtures are typically extruded through nozzle outlets of fairly simple dimensions.
In the field of prepared foods, extrusion techniques are used to create shaped items from large volumes of mixed material. After extrusion, the shaped items are further processed and packaged. These prepared food products are generally created from highly viscous mixed material that is shaped in the form of a rope, solid cylinder or solid pillow configuration. They may or may not include an encasement. It has generally been observed that these simple shapes result in minimum void creation in prepared food products.
Prepared food products must be of a size and weight suitable for individual consumption and they must be offered at prices competitive with similar food that is prepared at home. A hand-held prepared food product, for example, cannot be so large as to become unwieldy, yet it must be large enough to satisfy the targeted consumer class (i.e., adult or child). It has been determined that the rope shape is generally suitable for that purpose. The rope may be extruded and then cut into pieces of selectable length for additional processing. That processing may include crimping or folding of the cut ends and cooking, among other steps.
Unfortunately, the single tube or rope shape may not be suitable in the formation of all prepared and packaged food products that are acceptable to consumers and cost effective for the manufacturer to create. It is of increasing interest to form the prepared food as a pair of ropes joined together in a manner that allows them to be separated from one another easily and with minimal violation of the contents of the encasement. This arrangement allows for an increase in the quantity of the food within efficient package dimensions. If the product is to be formed as a pair of side-by-side rope shapes that are coupled together, the processing is substantially more involved. That is, either pairs of cut rope sections must be moved from an extrusion conveyor platform to a separate coupling stage, or two separate mix-and-extrude lines must be placed side-by-side. The first option adds considerably more processing delay and room for significant error in the coupling of the rope pairs. The second option requires the addition of a second mix and extrusion line and still requires a coupling together of the rope pairs, although that may be done on a single conveyor platform. These additional processing requirements increase the cost associated with creating prepared foods through an extrusion process.
Therefore, what is needed is a food preparation system and method that includes an efficient extrusion stage. What is needed is an extrusion stage that permits the formation of what is effectively a pair of side-by-side extrudates coupled together. Further, what is needed is an extrusion nozzle that creates such an extrudate with minimal void formation. More generally, what is needed is an extrusion nozzle and related processing for forming extrudates of coupled pairs.